In the following description, reference is essentially made to motor vehicle regulation and control algorithms without limiting the method according to the present invention to this application.
Functional models of motor vehicle regulation and/or control algorithms are generally hierarchically structured. Components are combined into functions in a stepwise manner during the development or modeling. A component limits outside access to internal data or signals by providing explicit interfaces. In addition, access to the interfaces of other components is explicitly specified by an interface description. A hierarchy composed of multiple functions may encompass the entire vehicle. A function contains a hierarchy composed of components.
The exchange of signals or data between components and functions likewise occurs via interfaces, or “ports.” For components which are described in greater detail below, actuators which are able to influence the physical or material characteristics of their surroundings and sensors which are able to detect the characteristics of their surroundings are controlled via these ports.
To maintain the clarity of models constructed in this manner, the visibility of sensor and actuator communication is locally limited (locality principle). If a sensor or actuator signal is required by only one component, the visibility of the signal is limited to this component.
A component which encapsulates a locally visible sensor or actuator signal is referred to as a sensor or actuator component. Other components are usually referred to as leaf components. Function-wide sensor or actuator signals are visible only within a function, whereas vehicle-wide sensor or actuator signals are visible on the highest hierarchical level of all functions.
The locality principle is implemented by locating the sensor or actuator components on the particular hierarchical level, and the placement of interfaces into the reading or writing components. The number of interfaces on the function and vehicle levels is significantly reduced via this procedure, and functional encapsulation of the sensor and actuator components is achieved.
This locality principle is violated when, according to the aforementioned rules, modeled functions are carried out on experimental hardware, for example rapid prototyping (RP) systems or electronic control units (ECU).
It is necessary to introduce into the model a set of sensor and actuator components which corresponds to the experimental hardware. The representation of these sensor and actuator components, referred to as platform software components, within the model depends on the actual characteristics of the experimental hardware, for example, the peripheral modules for microcontrollers of an ECU, or the input/output cards in RP systems.
These platform software components deliver the exact number of signals from the corresponding hardware module as inputs or outputs. For today's modeling tools, these components and therefore all inputs and outputs are defined on the highest hierarchical level and are therefore visible system-wide. This prevents local use of individual signals within the leaf components of a function hierarchy or component hierarchy.
As a result, unclear models are obtained which violate the locality principle described above.